WOODBURY - According to a new report released today, the number of American families who received their first foreclosure notice jumped 33 percent last month.The group RealtyTrac says it is the biggest monthly increase in foreclosure activity in four years. Experts say it shows banks are getting more aggressive in taking back properties. On Long Island, the situation is not as bleak. Last month, foreclosures fell in Nassau County by more than 21 percent and in Suffolk County by 64 percent.